This invention is generally directed to photoresponsive imaging members, and more specifically the present invention is directed to layered photoresponsive members having incorporated therein certain imidazole perinone pigment compositions. Thus, in one embodiment the present invention envisions the selection of specific imidazole perinone pigment compositions as organic photogenerator materials in photoresponsive imaging members containing therein arylamine hole transport molecules. The aforementioned photoresponsive imaging members can be negatively charged when the perinone photogenerating layer is situated between the hole transport layer and the substrate; or positively charged when the hole transport layer is situated between the photogenerating layer and the supporting substrate. Additionally, the photoresponsive imaging members with the perinone pigment compositions as photogenerator substances, and wherein the member further includes therein an aryl amine hole transport layer are useful in electrophotographic imaging processes, especially xerographic processes wherein negatively charged or positively charged images are rendered visible with developer compositions of the appropriate charge.
Layered photoresponsive imaging members are generally known, reference for example U.S. Pat. No. 4,265,900, the disclosure of which is totally incorporated herein by reference, wherein there is described an imaging member comprised of a photogenerating layer, and an aryl amine hole transport layer. Examples of substances useful in the photogenerating layer of this patent include trigonal selenium, metal phthalocyanines, and metal free phthalocyanines. Additionally, there is described in U.S. Pat. No. 3,121,006 a composite xerographic photoconductive member comprised of finely divided particles of a photoconductive inorganic compound dispersed in an electrically insulating organic resin binder. The binder components disclosed in the '006 patent comprise a material which is incapable of transporting for any significant distance injected charge carriers generated by the photoconductive particles. Illustrative examples of specific binder materials disclosed in the '006 patent include polycarbonate resins, polyester resins, polyamide resins, and the like.
Many other patents are in existence describing photoresponsive devices including layered devices containing generating substances, such as U.S. Pat. No. 3,041,167, which discloses an overcoated imaging member with a conductive substrate, a photoconductive layer, and an overcoating layer of an electrically insulating polymeric material. This member is utilized in an electrophotographic copying method by, for example, initially charging the member with an electrostatic charge of a first polarity, and imagewise exposing to form an electrostatic latent image which can be subsequently developed to form a visible image. Prior to each succeeding imaging cycle, the imaging member can be charged with an electrostatic charge of a second polarity, which is opposite in polarity to the first polarity. Sufficient additional charges of the second polarity are applied to create across the member a net electrical field of the second polarity. Simultaneously, mobile charges of the first polarity are created in the photoconductive layer such as by applying an electrical potential to the conductive substrate. The imaging potential, which is developed to form the visible image, is present across the photoconductive layer and the overcoating layer.
Photoresponsive imaging members with squaraine photogenerating pigments are also known, reference U.S. Pat. No. 4,415,639, the disclosure of which is totally incorporated herein by reference. In this patent there is illustrated an improved photoresponsive imaging member with a substrate, a hole blocking layer, an optional adhesive interface layer, an organic photogenerating layer, a photoconductive composition capable of enhancing or reducing the intrinsic properties of the photogenerating layer, and a hole transport layer. As photoconductive compositions for the aforementioned member, there can be selected various squaraine pigments, including hydroxy squaraine compositions. Moreover, there are disclosed in U.S. Pat. No. 3,824,099 certain photosensitive hydroxy squaraine compositions. According to the disclosure of this patent, the squaraine compositions are photosensitive in normal electrostatographic imaging processes.
The use of selected perylene pigments as photoconductive substances is also known. There is thus described in Hoechst European Patent Publication No. 0040402, DE3019326, filed May 21, 1980, the use of N,N'-disubstituted perylene-3,4,9,10,-tetracarboxyldiimide pigments as photoconductive substances. Specifically, there is disclosed in this publication evaporated N,N'-bis(3-methoxypropyl)perylene-3,4,9,10-tetracarboxyldiimide dual layered negatively charged photoreceptors with improved spectral response in the wavelength region of 400 to 700 nanometers. A similar disclosure is revealed in Ernst Gunther Schlosser, Journal of Applied Photographic Engineering, Vol. 4, No. 3, page 118 (1978). There are also disclosed in U.S. Pat. No. 3,871,881 photoconductive substances comprised of specific perlyene-3,4,9,10-tetracarboxylic acid derivative dyestuffs. In accordance with the teachings of this patent, the photoconductive layer is preferably formed by vapor depositing the dyestuff in a vacuum. Also, there is specifically disclosed in this patent dual layer photoreceptors with perylene-3,4,9,10-tetracarboxylic acid diimide derivatives, which have spectral response in the wavelength region of from 400 to 600 nanometers.
In U.S. Pat. No. 3,879,200 there are illustrated imaging members with perinones similar to some of the perinones of the present invention; however, this patent is silent with respect to layered imaging members with aryl amine hole transport layers. The aforementioned members of the present invention have advantages not possessed or disclosed in the '200 patent including, for example, improved electrical performance, and in some situations photosensitivity enhanced spectral response. Furthermore, layered imaging members with imidazole thiazinoperinone photogenerators and related components are illustrated in U.S. Pat. No. 4,517,270, and in Japanese Laid Open Publication Nos. 59-58433/84, and 59-59692/84. The aforementioned members of the present invention have advantages not possessed or disclosed in the Japanese publications, including improved electrical performance and increased spectral response as illustrated herein. The aforementioned advantages and other improvements achievable with the layered photoresponsive imaging member of the present invention reside primarily in the selection of the specific photogenerating pigments, particularly in a purified form, and the incorporation thereof into the imaging members with certain aryl amine compounds as charge transport layers, which aryl amines are more fully illustrated hereinafter.
While the above-described photoresponsive imaging members are suitable for their intended purposes, there continues to be a need for improved members, particularly layered members, having incorporated therein specific perinone pigment compositions and aryl amine hole transport compounds. Additionally, there continues to be a need for layered imaging members with acceptable visible sensitivity, low dark decay characteristics, high charge acceptance values comprised of specific aryl amine charge transport compositions; and as photogenerating materials perinone pigments; and wherein these members can be used for a number of imaging cycles in a xerographic imaging or printing apparatus. Furthermore, there continues to be a need for photoresponsive imaging members which can be positively or negatively charged thus permitting the development of images, including color images, with positively or negatively charged toner compositions. Moreover, there continues to be an important need for disposable imaging members with nontoxic organic pigments. Also, there is a need for disposable imaging members useful in xerographic imaging processes, and xerographic printing systems wherein, for example, light emitting diodes (LED), helium cadmium, or helium neon lasers are selected; and wherein these members are particularly sensitive to the visible region of the spectrum, that is, from about 400 to about 700 nanometers. Also, there is a need for low cost, high quality imaging members wherein reduced amounts of photosensitive materials can be selected.